21323210321 has 4 divisors (see below), whose sum is σ = 24369383232. Its totient is φ = 18277037412.

The previous prime is 21323210317. The next prime is 21323210387. The reversal of 21323210321 is 12301232312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21323210321 - 2² = 21323210317 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21323210293 and 21323210302.

It is not an unprimeable number, because it can be changed into a prime (21323210621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1523086445 + ... + 1523086458.

It is an arithmetic number, because the mean of its divisors is an integer number (6092345808).

Almost surely, 2^21323210321 is an apocalyptic number.

It is an amenable number.

21323210321 is a deficient number, since it is larger than the sum of its proper divisors (3046172911).

21323210321 is an equidigital number, since it uses as much as digits as its factorization.

21323210321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3046172910.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21323210321 its reverse (12301232312), we get a palindrome (33624442633).

The spelling of 21323210321 in words is "twenty-one billion, three hundred twenty-three million, two hundred ten thousand, three hundred twenty-one".